The ignition of a high intensity discharge (HID) lamp requires a voltage pulse across the electrodes of the lamp that is at least an order of magnitude higher than the normal operating line voltage. One conventional starting circuit for delivering such a voltage pulse includes a pulse transformer in combination with a capacitor and solid state components such as a sidac and transistor. Another conventional starting circuit uses nonlinear capacitors (such as barium titanate) with sidacs.
It is desirable for the lamp starting circuit to operate in proximity to or within the lamp. However, for in-situ applications, only non-linear capacitors can be used since the pulse transformer and capacitor combinations are too large for this purpose. Although nonlinear barium titanate capacitor devices can fit inside an HID lamp, the device has a limited operating temperature range that makes the starting of most hot HID lamps impossible.